The present invention relates to phenyl derivatives which are valuable blockers of chloride channels and as such useful for the treatment of sickle cell anaemia, brain oedema following ischaemia or tumours, diahreea, hypertension (diuretic) and for the reduction of the intraocular pressure for the treatment of disorders such as glaucoma. The compounds of the invention may also be useful in the treatment of allergic or inflammatory conditions and for the promotion of wound healing.
Chloride channels serve a wide variety of specific cellular functions and contribute to the normal function of skeletal and smooth muscle cells. Blockers of chloride channels are known to be useful in the treatment of brain oedema following ischaemia or tumours, diahreea, hypertension (diuretic) and for the reduction of the intraocular pressure in disorders such as glaucoma.
Sickle cell anaemia and the existence of sickle haemoglobin was the first genetic disease to be understood at the molecular level. The genetic defect underlying sickle cell anaemia causes the substitution of a single amino acid resulting in a mutant haemoglobin, sickle haemoglobin.
The physical manifestations of sickle cell disease is anaemia and painful ischaemic crises due to occlusion of the microcirculation by deformed erythrocytes (sickle cells). The primary cause of sickle erythrocyte deformation and distortion (or sickling) is a reversible polymerisation and gelation of sickle haemoglobin induced at the low oxygen tensions prevalent in metabolically active tissues. Sickle cells are also characterised by an enhanced cation permeability, resulting in cation depletion and cellular dehydration. Since the delay time for the polymerisation has been described as an extremely steep function of the sickle haemoglobin concentration itself, any decrease in cell volume will greatly increase the probability of sickling and thereby of vessel occlusion. Compounds which blocks the deoxygenation induced salt and volume (water) loss may delay the sickling process enough to avoid occlusion upon the passage of the sickle erythrocyte through metabolically active tissue. It has been estimated that a delay time of only 10 sec may suffice.
Several membrane ion channels and transporters present in normal erythrocytes has been suggested to participate in the altered membrane permeabilities of sickle cells. The favoured hypothesis has been stimulation of the Ca2+-activated K+-channel and several blockers of this channel has been suggested as therapeutic agents for the treatment of sickle-cell anaemia (Effects of Cetiedil on Monovalent Cation Permeability in the Erythrocyte: An explanation for the Efficacy of Cetiedil in the treatment of Sickle Cell Anaemia, Berkowitz, L. R., Orringer, E. P., Blood cells, (283-288 (1982) and U.S. Pat. No. 5.273.992). Since, K+ efflux through a K-channel must be followed by an equal efflux of Clxe2x88x92 to maintain electroneutrality, blockade of erythrocyte chloride channels are predicted to be as effective as blocking the K-channels itself. An advantage to the use of chloride channel blockers is that salt loss which may occur due to activation of unknown K-channel types will indirectly be blocked too.
The compounds of the present invention are valuable blockers of chloride channels as determined by concomitant measurements of conductive netfluxes of chloride and membrane potentials in suspensions of erythrocytes, and the compounds are therefore predicted to be useful for the treatment of ailments responsive to the blockade of chloride channels, including sickle cell anaemia.
The use of blockers of chloride channels for the treatment of sickle-cell anaemia form a new therapeutic approach.
Several chloride channel blockers and the use thereof have already been described in the technical literature:
Pflxc3xcgers Arch (1986), 407 (suppl. 2), pages 128-141 describe several compounds with chloride channel blocking activity. A very potent compound described herein is 5-nitro-2-(3-phenylpropylamino)benzoic acid. The reference do not disclose the use of chloride channel blockers for the treatment of sickle cell anaemia.
U.S. Pat. No. 5,489,612 describes Calixarene derivatives and their use as chloride channel blockers.
U.S. Pat. No. 4.994.493 describes certain 5-nitrobenzoic acid derivatives and their use in the treatment of cerebral oedema.
WO 96/16647 describes the use of chloride channel blockers for the reduction of the intraocular pressure and specifically the use of chloride channel blockers for the treatment of glaucoma.
It is an object of the present invention to provide a series of phenyl derivatives carrying an acidic group and pharmaceutically acceptable salts thereof which are useful in the treatment of disorders or diseases responsive to the blockade of chloride channels.
Still another object of the present invention is to provide a method of treating disorders or diseases responsive to the blockade of chloride channels, such as for example brain oedema following ischaemia or tumours, diahreea, hypertension (diuretic), glaucoma and in particular sickle-cell anaemia. A further object of the present invention is to provide a method for the treatment of allergic or inflammatory conditions and for the promotion of wound healing.
The invention then comprises, inter alia, alone or in combination:
A compound having the formula 
or a pharmaceutically acceptable salt thereof wherein
one of R1, R2 and R3 is a non-cyclic acidic group having a pKa value below 8 or a group which is in vivo convertible to such a group; R4, R5 and the other two of the substituents R1, R2 and R3 are each independently selected from hydrogen; alkyl; cycloalkyl; cycloalkylalkyl; alkenyl; alkynyl; alkoxy; hydroxy; halogen; trifluoromethyl; trifluoromethoxy; cyano; nitro; amino; and aryl, aralkyl, arylamino, aryloxy, aryl-COxe2x80x94, or heteroaryl, wherein the aryl and heteroaryl groups may be substituted one or more times with substituents selected from alkyl, cycloalkyl, cycloalkylalkyl, alkenyl, alkynyl, hydroxy, alkoxy, halogen, trifluoromethyl, trifluoromethoxy, cyano, nitro and amino; or R3 and R4 or R4 and R5 together form a fused 4 to 7 membered carbocyclic ring which may be unsaturated, or partially or fully saturated, while the other substituents R1, R2, R3, R4 and R5 is as defined above;.
Y is xe2x80x94COxe2x80x94, xe2x80x94CSxe2x80x94, xe2x80x94SO2xe2x80x94, or xe2x80x94C(xe2x95x90Nxe2x80x94R8)xe2x80x94, wherein R8 is hydrogen, alkyl, or cyano;
X is xe2x80x94NHxe2x80x94, xe2x80x94CH2xe2x80x94NHxe2x80x94, or xe2x80x94SO2xe2x80x94NHxe2x80x94;
Z is NR6, O, xe2x80x94CHxe2x95x90CHxe2x80x94, xe2x80x94Cxe2x89xa1Cxe2x80x94, xe2x80x94Nxe2x95x90CHxe2x80x94, or xe2x80x94CHxe2x95x90Nxe2x80x94; wherein R6 is hydrogen, or alkyl;
R11 R12, R13, R14 and R15 are each independently selected from hydrogen; alkyl; cycloalkyl; cycloalkylalkyl; alkenyl; alkynyl; alkoxy; hydroxy; halogen; trifluoromethyl; trifluoromethoxy; cyano; nitro; amino; xe2x80x94NHSO2xe2x80x94R7, xe2x80x94COOR7, xe2x80x94SO2N(R7)2, xe2x80x94SO2OR7 and xe2x80x94COxe2x80x94R7, wherein R7 is hydrogen, alkyl, cycloalkyl, cycloalkylalkyl, alkenyl, alkynyl, aryl or aralkyl; and aryl, aralkyl, arylamino, aryloxy, aryl-COxe2x80x94, or heteroaryl, wherein the aryl and heteroaryl groups may be substituted one or more times with substituents selected from alkyl, cycloalkyl; cycloalkylalkyl; alkenyl; alkynyl; hydroxy, alkoxy, halogen, trifluoromethyl, trifluoromethoxy, cyano, nitro and amino; or one of R11 and R12, R12 and R13, R13 and R14 or R14 and R15 together form a fused 4 to 7 membered carbocyclic ring which may be unsaturated, or partially or fully saturated, while the other substituents R11, R12, R13, R14 and R15 is as defined above;.
a compound as above wherein one of R1, R2 and R3 is NH2, xe2x80x94COOR9, xe2x80x94CH2COOR9, xe2x80x94CONH2, xe2x80x94NHSO2xe2x80x94R9, xe2x80x94SO2N(R9)2, xe2x80x94SO2OR9, xe2x80x94PO3H2, xe2x80x94PO3RH, xe2x80x94PO2NH2, xe2x80x94CONHOH, xe2x80x94CONHCN, xe2x80x94CONH2SO2R9 and xe2x80x94CONHNH2, wherein R9 is hydrogen, alkyl, cycloalkyl, cycloalkylalkyl, alkenyl, alkynyl, aryl or aralkyl, and the other of R1, R2 and R3 is as defined above;
a pharmaceutical composition comprising a therapeutically effective amount of a compound as above or a pharmaceutically acceptable salt thereof together with at least one pharmaceutically acceptable carrier or diluent;
the use of a compound as above for the preparation of a medicament for the treatment of a disorder or disease of a living animal body, including a human, which disorder or disease is responsive to the blockade of chloride channels;
the use of a compound as above for the preparation of a medicament for the treatment of sickle-cell anaemia, brain oedema following ischaemia, or tumours, diahreea, hypertension (diuretic), glaucoma, allergic or inflammatory conditions and ulcers;
a method for the treatment of a disorder or disease of a living animal body, including a human, which disorder or disease is responsive to the blockade of chloride channels, comprising administering to a living animal body in need thereof a therapeutically effective amount of a compound as above;
a method for the treatment of a disorder or disease of a living animal body which disorder or disease is sickle-cell anaemia, brain oedema following ischaemia, or tumours, diahreea, hypertension (diuretic), glaucoma, allergic or inflammatory conditions and ulcers comprising administering to such a living animal body, including a human, in need thereof a therapeutically effective amount of a compound as above;
a method for the preparation of a compound as above, comprising:
a) reacting a compound having the formula 
xe2x80x83wherein W is O, or S and R11, R12, R13, R14 and R15 is as defined above, with a compound having the formula 
xe2x80x83wherein R1, R2, R3, R4, R5 and R6 is as defined above, or
b) reacting a compound having the formula 
xe2x80x83wherein X, Y, R6, R11, R12, R13, R14 and R15 is as defined above, with a compound having the formula 
xe2x80x83wherein Hal is halogen and R1, R2, R3, R4 and R5 is as defined above,
whereafter the compound obtained is optionally converted to another compound of the invention and/or a pharmaceutically acceptable salt thereof is formed using conventional methods; and
the use of blockers of chloride channels of erythrocytes for the treatment of sickle cell anaemia.
Examples of pharmaceutically acceptable addition salts include inorganic and organic acid addition salts such as the hydrochloride, hydrobromide, phosphate, nitrate, perchlorate, sulfate, citrate, lactate, tartrate, maleate, fumarate, mandelate, benzoate, ascorbate, cinnamate, benzenesulfonate, methanesulfonate, stearate, succinate, glutamate, glycollate, toluene-p-sulphonate, formate, malonate, naphthalene-2-sulphonate, salicylate and the acetate. Such salts are formed by procedures well known in the art.
Other acids such as oxalic acid, while not in themselves pharmaceutically acceptable, may be useful in the preparation of salts useful as intermediates in obtaining compounds of the invention and their pharmaceutically acceptable acid addition salts.
Halogen is fluorine, chlorine, bromine or iodine.
Alkyl means a straight chain or branched chain of one to six carbon atoms, including but not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, and hexyl; methyl, ethyl, propyl and isopropyl are preferred groups.
Cycloalkyl means cyclic alkyl of three to seven carbon atoms, including but not limited to cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl;
Cycloalkylalkyl means cycloalkyl as above and alkyl as above, meaning for example, cyclopropylmethyl.
Alkenyl means a group of from two to six carbon atoms, including at least one double bond, for example, but not limited to ethenyl, 1,2- or 2,3-propenyl, 1,2-, 2,3-, or 3,4-butenyl.
Alkynyl means a group of from two to six carbon atoms, including at least one triple bond, for example, but not limited to ethynyl, 1,2-, 2,3-propenyl, 1,2-,2,3- or 3,4-butenyl.
Alkoxy is O-alkyl, wherein alkyl is as defined above.
Amino is NH2 or NH-alkyl or N-(alkyl)2, wherein alkyl is as defined above.
A non-cyclic acidic group having a pKa below 8 or a group which is in vivo convertible to such group include groups such as NH2, xe2x80x94COOR9, xe2x80x94CH2COOR9, xe2x80x94CONH2, xe2x80x94NHSO2xe2x80x94R9, xe2x80x94SO2N(R9)2, xe2x80x94SO2OR9, xe2x80x94PO3H2, xe2x80x94PO3RH, xe2x80x94PO2NH2, xe2x80x94CONHOH, xe2x80x94CONHCN, xe2x80x94CONH2SO2R9 and xe2x80x94CONHNH2, wherein R9 is hydrogen, alkyl, cycloalkyl, cycloalkylalkyl, alkenyl, alkynyl, aryl or aralkyl.
Heteroaryl is a 5- or 6-membered heterocyclic monocyclic group. Such a monocyclic heteroaryl group includes, for example, oxazol-2-yl, oxazol-4-yl, oxazol-5-yl, isoxazol-3-yl, isoxazol-4-yl, isoxazol-5-yl, thiazol-2-yl, thiazol-4-yl, thiazol-5-yl, isothiazol-3-yl, isothiazol-4-yl, isothiazol-5-yl, 1,2,4-oxadiazol-3-yl, 1,2,4-oxadiazol-5-yl, 1,2,4-thiadiazol-3-yl, 1,2,4-thiadiazol-5-yl, 1,2,5-oxadiazol-3-yl, 1,2,5-oxadiazol-4-yl, 1,2,5-thiadiazol-3-yl, 1,2,5-thiadiazol-4-yl, 1-imidazolyl, 2-imidazolyl, 4-imidazolyl, 1-pyrrolyl, 2-pyrrolyl, 3-pyrrolyl, 2-furanyl, 3-furanyl, 2-thienyl, 3-thienyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-pyrimidinyl, 4-pyrimidinyl, 5-pyrimidinyl, 3-pyridazinyl, 4-pyridazinyl, 2-pyrazinyl, 1-pyrazolyl, 3-pyrazolyl, and 4-pyrazolyl.
Aryl means an aromatic group such as phenyl or naphtyl.
Aralkyl means arylalkyl wherein alkyl and aryl is as defined above, meaning for example benzyl, or phenethyl.
I.p. means intraperetoneally, which is a well known route of administration.
P.o. means peroral, which is a well known route of administration.
Further, the compounds of this invention may exist in unsolvated as well as in solvated forms with pharmaceutically acceptable solvents such as water, ethanol and the like. In general, the solvated forms are considered equivalent to the unsolvated forms for the purposes of this invention.
It will be appreciated by those skilled in the art that the compounds of the present invention contain several chiral centres and that such compounds exist in the form of isomers (i.e. enantiomers). The invention includes all such isomers and any mixtures thereof including racemic mixtures.
Some of the compounds of the present invention exist in (+) and (xe2x88x92) forms as well as in racemic forms. Racemic forms can be resolved into the optical antipodes by known methods, for example, by separation of diastereomeric salts thereof with an optically active acid, and liberating the optically active amine compound by treatment with a base. Another method for resolving racemates into the optical antipodes is based upon chromatography on an optically active matrix. Racemic compounds of the present invention can thus be resolved into their optical antipodes, e.g., by fractional crystallization of d- or I- (tartrates, mandelates, or camphorsulphonate) salts for example. The compounds of the present invention may also be resolved by the formation of diastereomeric amides by reaction of the compounds of the present invention with an optically active activated carboxylic acid such as that derived from (+) or (xe2x88x92) phenylalanine, (+) or (xe2x88x92) phenylglycine, (+) or (xe2x88x92) camphanic acid or by the formation of diastereomeric carbamates by reaction of the compounds of the present invention with an optically active chloroformate or the like.
Additional methods for the resolvation of optical isomers, known to those skilled in the art may be used, and will be apparent to the average worker skilled in the art. Such methods include those discussed by J. Jaques, A. Collet, and S. Wilen in xe2x80x9cEnantiomers, Racemates, and Resolutionsxe2x80x9d, John Wiley and Sons, New York (1981).
The compounds of the invention may be prepared in numerous ways. The compounds of the invention and their pharmaceutically acceptable derivatives may thus be prepared by any method known in the art for the preparation of compounds of analogous structure, and as shown in the representative examples which follow.
The compounds of the present invention are potent blockers of chloride channels in normal as well as sickle cell erythrocytes. The ability of the compounds to block the erythrocyte chloride channels could not be demonstrated by classical electrophysiological measurements such as patch clamping, since the channel unit conductance is below the detection limit of these techniques.
All dose-response experiments were therefore performed by concomitant measurements of conductive netfluxes of Clxe2x88x92 (JCl) and membrane potentials (Vm) in suspensions of erythrocytes (Bennekou, P. and Christophersen, P. (1986), Flux ratio of Valinomycinxe2x80x94Mediated K+ Fluxes across the Human Red Cell Membrane in the presence of the Protronophore CCCP. J. Membrane Biol. 93, 221-227. ). The membrane Clxe2x88x92-conductances were calculated by the following equation (Hodgkin, A. L. and Huxley, A. F. (1952) The components of membrane conductance in the giant axon of loligo. J. Physiol. Lond. 116, 449-472):       G    Cl    =            F      *              J        Cl                    (                        V          m                -                  E          Cl                    )      
where F is the Faraday constant and ECl is the Nernst potential for the Cl-ion. Administration of N-(3-Trifluoromethylphenyl)-Nxe2x80x2-(2-carboxyphenyl) urea to a suspension of normal erythrocytes blocked GCl more than 95% with an IC50-value of 0.6 xcexcM. The compound equipotently blocked GCl from oxygenated as well as deoxygenated homozygoteous sickle cell erythrocytes.
Experimentally induced cell volume losses were measured as changes in the relative volume of packed cells. Inducing a massive water and salt loss (KCI) by addition the K+-ionophore valinomycin to the suspension for 5 min reduced the cell volume by 26%. N-(3-Trifluoromethylphenyl)-Nxe2x80x2-(2-carboxyphenyl) urea dose-dependently (IC50-value of 1.2 xcexcM) reduced the volume loss to 7%.
Deoxygenation induced permeability increases of sickle cells were estimated by measuring the extracellular K+-concentration vs time. Normal erythrocytes exhibited very small K+-fluxes, which was insensitive to deoxygenation and insensitive to 10 xcexcM N-(3-Trifluoromethylphenyl)-Nxe2x80x2-(2-carboxyphenyl) urea. The K+ flux from oxygenated sickle erythrocytes was 2-3 times higher than from normal erythrocytes and these fluxes was accelerated 4-8 times upon deoxygenation. In presence of N-(3-Trifluoromethylphenyl)-Nxe2x80x2-(2-carboxyphenyl) urea (10 xcexcM) the basal K+-flux from sickle erythrocytes was normalised and the deoxygenation induced flux component were nearly abolished.
N-(3-Trifluoromethylphenyl)-Nxe2x80x2-(2-carboxyphenyl) urea was non-toxic to mice at concentrations up to 150 mg/kg i.p. and i.v.
While it is possible that, for use in therapy, a compound of the invention may be administered as the raw chemical, it is preferable to present the active ingredient as a pharmaceutical formulation.
The invention thus further provides pharmaceutical formulations comprising a compound of the invention or a pharmaceutically acceptable salt or derivative thereof together with one or more pharmaceutically acceptable carriers therefor and, optionally, other therapeutic and/or prophylactic ingredients. The carrier(s) must be xe2x80x9cacceptablexe2x80x9d in the sense of being compatible with the other ingredients of the formulation and not deleterious to the recipient thereof.
Pharmaceutical formulations include those suitable for oral, rectal, nasal, topical (including buccal and sub-lingual), vaginal or parenteral (including intramuscular, sub-cutaneous and intravenous) administration or in a form suitable for administration by inhalation or insufflation.
The compounds of the invention, together with a conventional adjuvant, carrier, or diluent, may thus be placed into the form of pharmaceutical compositions and unit dosages thereof, and in such form may be employed as solids, such as tablets or filled capsules, or liquids such as solutions, suspensions, emulsions, elixirs, or capsules filled with the same, all for oral use, in the form of suppositories for rectal administration; or in the form of sterile injectable solutions for parenteral (including subcutaneous) use. Such pharmaceutical compositions and unit dosage forms thereof may comprise conventional ingredients in conventional proportions, with or without additional active compounds or principles, and such unit dosage forms may contain any suitable effective amount of the active ingredient commensurate with the intended daily dosage range to be employed. Formulations containing ten (10) milligrams of active ingredient or, more broadly, 0.1 to one hundred (100) milligrams, per tablet, are accordingly suitable representative unit dosage forms.
The compounds of the present invention can be administrated in a wide variety of oral and parenteral dosage forms. It will be obvious to those skilled in the art that the following dosage forms may comprise, as the active component, either a compound of the invention or a pharmaceutically acceptable salt of a compound of the invention.
For preparing pharmaceutical compositions from the compounds of the present invention, pharmaceutically acceptable carriers can be either solid or liquid. Solid form preparations include powders, tablets, pills, capsules, cachets, suppositories, and dispersible granules. A solid carrier can be one or more substances which may also act as diluents, flavouring agents, solubilizers, lubricants, suspending agents, binders, preservatives, tablet disintegrating agents, or an encapsulating material.
In powders, the carrier is a finely divided solid which is in a mixture with the finely divided active component.
In tablets, the active component is mixed with the carrier having the necessary binding capacity in suitable proportions and compacted in the shape and size desired.
The powders and tablets preferably contain from five or ten to about seventy percent of the active compound. Suitable carriers are magnesium carbonate, magnesium stearate, talc, sugar, lactose, pectin, dextrin, starch, gelatin, tragacanth, methylcellulose, sodium carboxymethylcellulose, a low melting wax, cocoa butter, and the like. The term xe2x80x9cpreparationxe2x80x9d is intended to include the formulation of the active compound with encapsulating material as carrier providing a capsule in which the active component, with or without carriers, is surrounded by a carrier, which is thus in association with it. Similarly, cachets and lozenges are included. Tablets, powders, capsules, pills, cachets, and lozenges can be used as solid forms suitable for oral administration.
For preparing suppositories, a low melting wax, such as admixture of fatty acid glycerides or cocoa butter, is first melted and the active component is dispersed homogeneously therein, as by stirring. The molten homogenous mixture is then poured into convenient sized molds, allowed to cool, and thereby to solidify.
Formulations suitable for vaginal administration may be presented as pessaries, tampons, creams, gels, pastes, foams or sprays containing in addition to the active ingredient such carriers as are known in the art to be appropriate.
Liquid form preparations include solutions, suspensions, and emulsions, for example, water or water-propylene glycol solutions. For example, parenteral injection liquid preparations can be formulated as solutions in aqueous polyethylene glycol solution.
The compounds according to the present invention may thus be formulated for parenteral administration (e.g. by injection, for example bolus injection or continuous infusion) and may be presented in unit dose form in ampoules, pre-filled syringes, small volume infusion or in multi-dose containers with an added preservative. The compositions may take such forms as suspensions, solutions, or emulsions in oily or aqueous vehicles, and may contain formulatory agents such as suspending, stabilising and/or dispersing agents. Alternatively, the active ingredient may be in powder form, obtained by aseptic isolation of sterile solid or by lyophilisation from solution, for constitution with a suitable vehicle, e.g. sterile, pyrogen-free water, before use.
Aqueous solutions suitable for oral use can be prepared by dissolving the active component in water and adding suitable colorants, flavours, stabilizing and thickening agents, as desired.
Aqueous suspensions suitable for oral use can be made by dispersing the finely divided active component in water with viscous material, such as natural or synthetic gums, resins, methylcellulose, sodium carboxymethylcellulose, or other well known suspending agents.
Also included are solid form preparations which are intended to be converted, shortly before use, to liquid form preparations for oral administration. Such liquid forms include solutions, suspensions, and emulsions. These preparations may contain, in addition to the active component, colorants, flavours, stabilizers, buffers, artificial and natural sweeteners, dispersants, thickeners, solubilizing agents, and the like.
For topical administration to the epidermis the compounds according to the invention may be formulated as ointments, creams or lotions, or as a transdermal patch.
Ointments and creams may, for example, be formulated with an aqueous or oily base with the addition of suitable thickening and/or gelling agents. Lotions may be formulated with an aqueous or oily base and will in general also contain one or more emulsifying agents, stabilising agents, dispersing agents, suspending agents, thickening agents, or colouring agents.
Formulations suitable for topical administration in the mouth include lozenges comprising active agent in a flavoured base, usually sucrose and acacia or tragacanth; pastilles comprising the active ingredient in an inert base such as gelatin and glycerin or sucrose and acacia; and mouthwashes comprising the active ingredient in a suitable liquid carrier.
Solutions or suspensions are applied directly to the nasal cavity by conventional means, for example with a dropper, pipette or spray. The formulations may be provided in single or multidose form. In the latter case of a dropper or pipette, this may be achieved by the patient administering an appropriate, predetermined volume of the solution or suspension. In the case of a spray, this may be achieved for example by means of a metering atomising spray pump.
Administration to the respiratory tract may also be achieved by means of an aerosol formulation in which the active ingredient is provided in a pressurised pack with a suitable propellant such as a chlorofluorocarbon (CFC) for example dichlorodifluoromethane, trichlorofluoromethane, or dichlorotetrafluoroethane, carbon dioxide, or other suitable gas. The aerosol may conveniently also contain a surfactant such as lecithin. The dose of drug may be controlled by provision of a metered valve.
Alternatively the active ingredients may be provided in the form of a dry powder, for example a powder mix of the compound in a suitable powder base such as lactose, starch, starch derivatives such as hydroxypropylmethyl cellulose and polyvinylpyrrolidone (PVP). Conveniently the powder carrier will form a gel in the nasal cavity. The powder composition may be presented in unit dose form for example in capsules or cartridges of, e.g., gelatin, or blister packs from which the powder may be administered by means of an inhaler.
In formulations intended for administration to the respiratory tract, including intranasal formulations, the compound will generally have a small particle size for example of the order of 5 microns or less. Such a particle size may be obtained by means known in the art, for example by micronization. When desired, formulations adapted to give sustained release of the active ingredient may be employed.
The pharmaceutical preparations are preferably in unit dosage forms. In such form, the preparation is subdivided into unit doses containing appropriate quantities of the active component. The unit dosage form can be a packaged preparation, the package containing discrete quantities of preparation, such as packeted tablets, capsules, and powders in vials or ampoules. Also, the unit dosage form can be a capsule, tablet, cachet, or lozenge itself, or it can be the appropriate number of any of these in packaged form.
Tablets or capsules for oral administration and liquids for intravenous administration are preferred compositions.
The compounds of the present invention are, due to their potent chloride channel blocking activity, useful in the treatment of sickle cell anaemia, brain oedema following ischaemia or tumors, diahreea, and hypertension (diuretic) as well as other disorders responsive to the blockade of chloride channels. The compounds of the invention may also be useful in the treatment of allergic and inflammatory conditions, for the promotion of wound healing or the treatment of ulcers. The compounds of this invention may accordingly be administered to a living animal body, including a human, in need of treatment, alleviation, or elimination of an indication associated with or responsive to chloride channel blocking activity. This includes especially sickle cell anaemia, brain oedema following ischaemia or tumors, diahreea, and hypertension (diuretic).
Suitable dosage range are 0.1-500 milligrams daily, and especially 10-70 milligrams daily, administered once or twice a day, dependent as usual upon the exact mode of administration, form in which administered, the indication toward which the administration is directed, the subject involved and the body weight of the subject involved, and further the preference and experience of the physician or veterinarian in charge.